As electronic components have become smaller, it has become more important to securely bond electronic components and printed boards. Electronic components and printed boards are bonded to each other by connecting lead terminals of the electronic components and electrode pads on the printed boards with solder, which serves as a base material. Hereinbelow, the electrode pads may be referred to as “electrodes”.
For example, in a reflow process in a surface mount technology (SMT), as illustrated in FIG. 18, bonding portions are formed by melting solder 403 provided on electrode pads 402, allowing the solder 403 to flow toward lead terminals 401 and to harden.
The molten solder 403 wicks up the lead terminals 401 by surface tension. At this time, a large amount of solder 403 flows toward the electronic component (the lead terminals 401).
As a result, the amount of solder 403 between the lead terminals 401 and the electrode pads 402 becomes insufficient, producing gaps G, as illustrated in FIG. 19A, which leads to poor bonding.
Furthermore, as illustrated in FIG. 19B, the solder 403 forms a solder deposit at the bases, on the electronic component side, of the lead terminals 401. This solder deposit and the solder 403 on the adjacent lead terminal 401 may cause a short-circuiting (a short-circuited portion S).
Therefore, a surface having low solder wettability (a wicking prevention area) is provided on the lead terminals to suppress wicking. The solder-wicking prevention area is provided by a forming nickel (Ni) surface, which has low solder wettability, on a predetermined part of a gold (Au) surface, which has high solder wettability.
The solder-wicking prevention area having a linear shape extending perpendicular to the direction in which solder wicks is formed by, for example, removing Au plating by laser beam machining or etching to expose Ni plating on the base material, i.e., copper (Cu).
As illustrated in FIGS. 20A and 20B, if a solder-wicking prevention area 401a of the lead terminal 401 has a width of, for example, 0.02 mm, solder (403-1 to 403-3) flows over the solder-wicking prevention area 401a in a solder-wicking direction D.
In contrast, as illustrated in FIGS. 21A, 21B, and 22, if a solder-wicking prevention area 401b of the lead terminal 401 has a width of, for example, 0.2 mm, solder (403-11 to 403-13) does not flow over the solder-wicking prevention area 401b. 
As has been described, a wider solder-wicking prevention area has a better solder-wicking preventing performance. However, forming a wider solder-wicking prevention area may use higher laser output or longer laser irradiation time. If higher laser output is to be obtained, a laser device having a higher output has to be used, and if longer laser irradiation time is to be obtained, longer machining time (cycle time) has to be taken. In either case, a great deal of electric power is consumed. Related art includes Japanese Laid-open Patent Publication Nos. 4-199551, 2004-152750, 2007-173224, and 2007-179922, and International Application Publication No. WO2007/24005.